Young children learning language are faced with an enormous problem of induction. When an adult points to an object and labels it with an unfamiliar word, there are an indefinite number of possible interpretations for the new world. Yet children seem to learn words very quickly with the limited experience of having heard them used as object labels. This suggests that children have expectations about the meanings of words that constrain the range of possible interpretations of a newword. For example, children may expect that object labels refer to taxonomic categories with perceptually similar members (e.g., chair, dog). These categories, which have been called basic level categories, are in fact the first learned by children. However, if a "basic level constraint" exists, then we are faced with another puzzle. How do children eventually learn that there are also categories at other hierarchical levels, both more general (e.g., furniture, animal), and more specific (e.g., rocking chair, collie). Parents' labelling routines may structure the environment in ways that help children to determine the hierarchical level of category terms. In previous research, I have found systematic strategies that parents use to teach categories at different levels. In the proposed studies, I plan to explore the relationship between the constraints on children's expectations about word meanings and the category information presented to children by parents. More specifically, do parents' strategies for introducing non-basic category labels alter children's expectation that object labels refer to basic level categories?